There has been devised an object detection device for determining whether or not an object for detection is present in an image photographed by a camera or the like. An object detection device is mounted onto a vehicle, together with a camera, for example. An object detection device determines whether or not a human is present in an image photographed by a camera, to thereby inform a driver of the presence of the human. With the use of the object detection device, the driver of the vehicle can easily grasp an external situation of the vehicle.
An object detection device employs algorithms of a neural network having a learning function, a support vector machine, and the like, in order to determine whether or not an object for detection is present in an image. An object detection device sets an area where an object is to be detected (detection window area) in an input image. An object detection device then determines whether or not an object for detection is included in an image within the detection window area by using a program in which the above-described algorithm is implemented.
For example, an object detection device according to Patent Document 1 makes a similarity histogram by using an image including a human and an image including an object other than a human, and determines whether or not an object for detection is present in an image within a detection window area with the use of the similarity histogram.
An image recognition apparatus according to Patent Document 2 detects a pedestrian in an image photographed by a vehicle-mounted camera. More specifically, when a potential object which is likely to be a pedestrian is detected in an image by using a neural network, the image recognition apparatus according to Patent Document 2 compares the potential object with a head, arms, legs, and the like which compose a pedestrian, to thereby determine whether or not the potential object is a pedestrian.
An image recognition apparatus according to Patent Document 3 sets a plurality of detection windows respectively including areas for detection which partly overlap with each other, and performs a pattern matching process on each of the detection windows with the use of a standard pattern of an object for recognition (such as a pedestrian). In the image recognition apparatus according to Patent Document 3, if a pattern matching process is performed a plurality of times on one area, respective results of the pattern matching processes for the one area is integrated. Then, based on the result of the integration, the position of a pedestrian is specified.